Heating, cooling, and conditioning the environment condition of a building generally account for a substantial portion of energy usage within a residential building. Occupants of residential buildings may employ programmable thermostats (also referred to as setback thermostats or clock thermostats) to control or adjust the temperature set-points in the buildings. The building occupants may program their programmable thermostat to reduce the heating or cooling operation over a portion of the day, for example, when the premises are vacated or when the occupants are asleep. A programmable thermostat may also include control devices that receive a control signal, including a temperature set-point or a setback signal, via a communication port from an external source, to control or adjust its set-point or to temporarily disable its heating or cooling function.